These procedures continued for 2 to 5 years, normally, at the end of which time the senior doctor gave the new physician a piece of paper saying that the new doctor had fully completed his apprenticeship. This type of medical education could produce good doctors, yet it all depended on the caliber of the older practitioner and how good a tutor he was.  Still this was the only medical education available in the colonies for 160 years and remained prominent well into the nineteenth century.